How to select an item in a Jface TableViewer after a dialog becomes activated

Scenario : We have a Jface Dialog and a TableViewer or a TreeViewer on that dialog. after the dialog become active we want to select an item and want to fire the TableViewers selection listener.


Step 1. Add a selection listener to the TableViewer :

Note : You should do this in createDialogArea() method.

  getTableViewer().addSelectionChangedListener(new ISelectionChangedListener() {  
   @Override  
   public void selectionChanged(SelectionChangedEvent event) {  
   final Object selection = getSingleSelection(event.getSelection());  
   if (selection instanceof SomeObject) {  
    DoSomething();  
   }  
   }  
  });  
  }  

Step 2. Add a Shell Listner :(again in createDialogArea() method)

  getShell().addShellListener(new ShellAdapter()  
  {  
   @Override  
   public void shellActivated(ShellEvent e) {    
   super.shellActivated(e);  
   if (getLines().size()>0) {  
    getViewer().getControl().setFocus();  
    getTableViewer().setSelection(new StructuredSelection(get.getElementAt(0)),true);  
   }  
   }  
  });  

You are done ! now after the shell become active the first item of the TableViews will be selected and a selection listner will be fired . Enjoy!

Css Stying in E4 Compatibility Layer

I can apply Css Styling  in my Eclipse 3.x plugin using following steps:

Step 1. Configuring CSS Stylesheets:


1.1 add a css file

1.2 add a theme using theme extension point

1.3

Step 2. add css id/class to your swt control:

final Composite composite = new Composite(parent, SWT.NONE);
composite.setData("org.eclipse.e4.ui.css.id","MyCSSTagForLabel");

Step 3. add the folowing block to your default.css file:

#MyCSSTagForLabel{

  color: black;

  background: #99b4d1;

  swt-corner-radius: 20;

}

Done!

Eclipse RCP : How to check state(toggle) of a menu items or toolbar items inside handlers

In Eclipse RCP there are at-least two different ways we  can check the state of a menu item or  a toolbar item inside a handlers execute method :

Option 1 :

ICommandService service =(ICommandService) PlatformUI.getWorkbench().getService(ICommandService.class);

Command command = service.getCommand("org.eclipse.example.command.toggle");

State state = command.getState("org.eclipse.example.command.toggleState");

System.out.println(state.getValue());

//state.setValue(!(Boolean) state.getValue());

Option 2:

   @Override

    public Object execute(ExecutionEvent event) throws ExecutionException {

   

   

        Event selEvent = (Event) event.getTrigger();

        Widget widget =  selEvent.widget;

        if (widget instanceof ToolItem) {        

        isSelected = ((ToolItem)widget).getSelection();

}else {

isSelected = ((MenuItem)widget).getSelection();

}

}

Eclipse RCP : How to check a view is currenlty visible

If we need to check whether a view currently available or visible we can use following code :

Boolean result = false;

IViewReference viewReferene =  PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().findViewReference("my_view_id");


if (viewReferene != null) {
result = true;
}

How to Enable and Disable VNC server password authentication in cent os

You can switch between password and non password mode by:

# vi /etc/X11/xorg.conf  (enable password)

[..]

    #Option "SecurityTypes" "None"

    Option "SecurityTypes" "VncAuth"

    Option "UserPasswdVerifier" "VncAuth"

    Option "PasswordFile" "/root/.vnc/passwd"

[..]

# vi /etc/X11/xorg.conf  (disable password)

[..]

    Option "SecurityTypes" "None"

    #Option "SecurityTypes" "VncAuth"

    #Option "UserPasswdVerifier" "VncAuth"

    #Option "PasswordFile" "/root/.vnc/passwd"

[..]

Restart X for change to take effect:

# init 3   (wait a few seconds - )

# init 5

after enabling the password: 

You should be able to type ”vncpasswd” from the terminal as root. This will enable you to type in a new password for the VNC connection.

Configure log4j properties file for logging both in file system and console

# Root logger option
log4j.rootLogger= DEBUG,errorLogger,stdout,



# Direct log messages to a log file
log4j.appender.errorLogger=org.apache.log4j.RollingFileAppender
log4j.appender.errorLogger.Threshold = ERROR
log4j.appender.errorLogger.File=.\\Log\\logging.log
log4j.appender.errorLogger.MaxFileSize=1MB
log4j.appender.errorLogger.MaxBackupIndex=1
log4j.appender.errorLogger.layout=org.apache.log4j.PatternLayout
log4j.appender.errorLogger.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

# Direct log messages to stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

The above configuration will write only error log to file system and all the other log in console.

log4j.appender.errorLogger.Threshold = ERROR   does the trick.

Eclipse Jobs API : Perform something when job is done

When we need to do something for example notify user or cleaup someting after a JOB is finished we can user the  JobChangeListener to accomplish this. see the folowing code:

     final Job job = new Job("Long Running Job") {
        protected IStatus run(IProgressMonitor monitor) {
           try {
              while(hasMoreWorkToDo()) {
                 // do some work
                 // ...
              if (monitor.isCanceled()) return Status.CANCEL_STATUS;
             }
              return Status.OK_STATUS;
           } finally {
              schedule(60000); // start again in an hour
           }
        }
     };
  job.addJobChangeListener(new JobChangeAdapter() {
        public void done(IJobChangeEvent event) {
        if (event.getResult().isOK())
           postMessage("Job completed successfully");
           else
              postError("Job did not complete successfully");
        }
     });
  job.setSystem(true);
     job.schedule(); // start as soon as possible

See the details in following website:

https://eclipse.org/articles/Article-Concurrency/jobs-api.html